Pentamethylmolybdenum is an organomolybdenum compound containing five methyl groups bound to a central molybdenum atom.

[2] The shape of the molecule is a square pyramid.

[3] Pentamethylmolybdenum can be prepared from molybdenum pentachloride and dimethyl zinc at low temperature between −70 and −20.

Another possible creation route, is from molybdenum oxychloride.

It turns black when exposed to air, or heated over −10°C.